Effect of composition on structural evolution and NMR parameters of quadrupolar nuclides in sodium borate and aluminoborosilicate glasses: a view from high-resolution 11B, 27Al, and 17O solid-state NMR

Abstract

In this study, using 11B, 27Al, and 17O 3QMAS NMR spectroscopy, we investigated the compositional effect on the structures (particularly, topological evolution of boron species and their spatial proximity) and the NMR parameters of B, Al, and O configurations in binary sodium borate and sodium aluminoborosilicate glasses in NaBSiO4–NaAlSiO4 and NaBSi3O8–NaAlSi3O8 joins. Noble structural findings of the current study include the two distinct [4]B species in sodium borate glasses with low alkali content and the presence of Na–O–B peak in NaAl0.25B0.75SiO4 glasses. The proximity between [3]B and [4]B in NaAlSiO4-NaBSiO4 glasses was revealed via 11B double quantum MAS NMR. The changes in quadrupolar coupling constants and isotropic chemical shift for diverse coordination B and Al environments and oxygen clusters provide improved insights in the effect of composition on the changes in the 2nd nearest neighbors environments and the extent of topological distortion.